Display screen or portion thereof including a graphical user interface



FIG. 1 is front view of the display screen or portion thereof including a graphical user interface showing our new design;

FIG. 2 is a front perspective view thereof; and,

FIG. 3 is an enlarged view of an icon shown on graphical user interface.

The broken line showing of a display screen including a graphical user interface is included for the purpose of illustrating portions of the article and forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof including a graphical user interface, as shown and described. 